WMgo lllli Precautions for Poar Poymer Anayss~ Interfering interactions likely to be observed ~Methods to reduce interactionsElution will beacceleratedExclusionlimit volumeElution will be delayedPermeationlimit volume Unexpected interactions in the column can affect the size exclusion chromatography analysis of polar polymers.These interactions may change elution patterns and results in an invalid molecular weight calculation.It is important to reduce these interfering interactions in order to obtain the accurate molecular weight distribution.Interactions between the analyte and the packing materials Hydrophobic interaction The analyte is adsorbed on the packing material. This delays the analyte elution and results in under estimating the analyte's molecular weight. See (B) and (D). Ionic interaction (1) Ion Exclusion The analyte is repelled from the packing material. This accelerates the analyte elution and results in over estimating the analyte's molecular weight. See (A) and (C). (2) Ion Exchange The analyte is adsorbed onto the packing material. This delays the analyte elution and results in under estimating the analyte's molecular weight. See (B) and (D).Interaction within and between the analyte Ionic repulsion effects observed within the multivalent macromolecules causes structure expansion This accelerates the analyte elution and results in over estimating the analyte's molecular weight. See (A). Association between the molecules This accelerates the analyte elution and results in over estimating the analyte's molecular weight. See (A). Interactions between the analyte and the solvent The multivalent ion in the solvent works as a bridge to bind ionic molecules (analyte).Ionic interaction Add salt into the eluentHydrophobic interaction Increase the analyte dissociation Cationic polymer Anionic polymer Lower the eluent pH Higher the eluent pH Lower the eluent polarity e.g. Add acetonitrile or methanolAqueous SEC (GFC)Exclusion limitmolecular weightIonic interaction Add salt into the eluent e.g. Add LiBr to DMF Add CF3COONa to HFIPHydrophobic interaction Lower the eluent polarity e.g. Change the eluent from DMF to THFHydrophilic interaction Increase the eluent polarity e.g. Change the eluent from THF to DMFOrganic SEC (GPC)(A)(C)(B)(D)11Precautions for Polar Polymer Analysis
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